In the case of capacitor covers of this type, generally two connecting elements passing through the cover are provided for electrical connection to electrodes of a capacitor winding located in the capacitor can. The connecting elements normally pass through apertures in the cover from the inside to the outside and are anchored within the cover part in a positive locking and force-fitting manner. As a result of the different thermal coefficients of expansion of metal and plastic as well as the frequently inadequate rotation protection of the connecting elements when seated in the apertures, there is a risk of the connecting elements becoming loose and as a result, leaks may develop in the aperture area.
In addition, in order to accommodate a valve element, which is generally formed of elastomeric material, an additional aperture is provided in the cover part which has a smooth wall surface in order to ensure adequate gas-tightness. Previously, in order to ensure the desired gas-tightness, the cover parts generally were produced as plastic moldings of relatively costly design. However, the known cover parts of this type are inadequate with respect to the thermal load capacity as well as the desired mechanical and chemical characteristics. Furthermore, it is known in the case of electrolytic capacitors, to make the cover parts of coated hard-paper material. These covers are distinguished by a relatively high temperature resistance. The connecting elements were engaged within the apertures in a manner similar to simple riveted connections. However, rotation protection could not be ensured in this way. In addition, no valve elements could be accommodated in these cover parts.
In view thereof, the invention is based on the object of developing a cover arrangement of the aforementioned type which, despite a simple construction of the cover part, provides rotation-protected and gas-tight fitting of the connecting elements and valve elements within the apertures and provides a good load capacity and resistance, both from the mechanical and the chemical viewpoints.